Muscular System Part 2

Put the in the correct order the events of Skeletal Muscle contraction:

1. cross-bridge cycling

2. Events at the neuromuscular junction

3. Muscle fiber excitation

4. Excitation-contraction coupling

T/F Junctional folds are infoldings of sarcoplasm.

• TRUE

• FALSE

The space between the neuron and the muscle is the ___________.

• Motors unit

• Synaptic Cleft

• End Plate

• M line

The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is stimulated is known as the ___________.

• membrane repolarization

• membrane hyperpolarization

• resting potential

• motor end potential

• Action potential

Muscle contraction is dependent on the efflux of _____from the sarcoplasmic reticulum.

• Sodium

• Potassium

• Calcium

• Chloride

Tags

NGSS.HS-LS2-3

Which one of the following binds calcium ions in a skeletal muscle, causing contraction?

• Myosin

• Troponin

• Calmodulin

• Tropomyosin

• Action

T/F: Cross bridge cycle is a series of events during which actin heads pull thin filaments toward the center of the sarcomere.

• TRUE

• FALSE

What is the cause of rigor mortis?

• Breakdown of protein in the cell after death

• calcium influx into the sarcoplasm after death

• high levels of sodium in the cell after death

• diffusion of potassium out of the cell after death

Motor neuron and all muscles fibers it supplies

What happens in the neuromuscular junction? Put in order

1. Acetylcholinesterase degrades Ach

2. ACh diffuses across to ACh receptors (Na+ chemical gates) on the sarcolemma

3.AP arrives at the axon terminal

4. Calcium entry causes the release of ACh neurotransmitter into the synaptic cleft

5. ACh binding to receptors, opens gates, allowing Na+ to enter resulting in end-plate potential

6. Voltage-gated calcium channels open, calcium enters the motor neuron